Generally speaking, the tongue coating is pink and tender. If it turns yellow, it may预示pathological abnormalities. A yellow and greasy tongue coating is related to the mouth, and it may also be accompanied by a bitter taste. This condition is related to many factors and cannot be ruled out that it is caused by gastrointestinal diseases. Attention should be paid to diet.

A yellow and greasy tongue coating can be seen not only in healthy individuals but also in the early stages of light deviations and during the recovery period of diseases. Because the pathological changes in the body are not obvious, the changes in the tongue coating are also close to the normal thin and yellow tongue coating.

Some diseases with only subjective symptoms without organic lesions, such as neurasthenia and gastrointestinal neurosis, may have a yellow and thin greasy tongue coating. This is often seen in the early stages of disease or localized lesions that have not affected the whole body, such as goiter during adolescence, trauma, tinea pedis, qi retention, early breast cancer, and cervical cancer. Since there are no symptoms or the lesions are localized and have not affected the circulation of Qi and blood in the whole body, the tongue coating remains thin and yellow, which is within the normal range. However, as the disease progresses, the tongue coating may also change.

A yellow tongue coating can appear in patients with internal retention of dampness or fluid retention, such as certain patients with pleural effusion, ascites, chronic nephritis, asthma, chronic bronchitis, and bronchiectasis. The presence of dampness or phlegm retention in these patients leads to a thick and yellow or greasy tongue coating.

In most cases, a yellow and greasy tongue coating with a bitter taste is formed by the combination of pathogenic heat and phlegm-dampness. A yellow tongue coating indicates heat, while a greasy coating indicates dampness, phlegm, and food retention. Therefore, a yellow and greasy tongue coating is often a sign of damp-heat, but it can also be caused by Qi deficiency and dysfunction, leading to dampness obstruction.